Lavoisier grouped the elements into four categories on the basis of their chemical properties:
1. Simple substances.
4. Earthy Substances
1817 - 1829
Dobereiner began to group elements with similar properties into groups of three, or triads.
1864 - 1870
Over 1864 - 1870 Meyer produced several revised versions of the periodic table. This 1868 table listed the elements in order of atomic weight, with elements with the same valency arranged in vertical lines which was incredibly similar to Mendeleev’s table
The law of octaves was created, which ordered the periodic elements by their atomic weight
In 1869 Newlands Octave Law was rejected
Mendeleev arranged the periodic table based on atomic weight, then he discovered that this put the elements in groups such as non-metals or noble gases. When he created this version of the periodic table in 1871 he created periodic law.
Dobreiner showed that in specific triads, the mean of the lightest and heaviest atom equalled to the middle element
1938 - 1952
Glenn Seaborg co-discovered ten elements (plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and element 106 (seaborgium)).